The present invention relates to automotive seating, and more particularly to a recliner mechanism for an automotive seat.
An automotive seat assembly typically includes a seat frame mounted for forward and rearward movement on a rail mechanism. The seat frame generally includes a cushion frame and a back frame that are separately attached to the rail mechanism. If desired, the cushion frame can be mounted to the rail mechanism upon a conventional height adjustment assembly that permits adjustment of the height and/or the angle of the cushion frame.
The back frame is mounted to the rail mechanism by a recliner mechanism that permits the back frame to pivot or recline with respect to the rail mechanism and cushion frame. The recliner mechanism typically includes a rail arm attached to the rail mechanism and a back frame arm attached to the back frame. The two arms of the recliner mechanism are pivotally interconnected to permit selective adjustment of the angle between the back frame and the rail mechanism.
The angle of the recliner mechanism and consequently the seat back is controlled by a recliner control assembly that can be operated by the seat occupant. Recliner control assemblies are available in a wide variety of designs. One type of recliner control assembly includes a "turnbuckle-style" adjustment mechanism. In this design, the adjustment mechanism includes a first externally-threaded rod pivotally mounted to the rail mechanism, a second externally-threaded rod pivotally mounted to the back frame arm of the recliner mechanism, and an internally threaded drive block extending between and operatively interconnecting the two legs. The two rods are threaded in opposite directions so that rotation of the drive block causes the rods to move toward and away from each other in the same manner as a conventional turnbuckle. Movement of the rods toward and away from each other varies the overall length of the adjustment mechanism which in turn causes the back frame arm and back frame to pivot. The turnbuckle-style adjustment mechanism suffers in that the drive block moves linearly with respect to the rail mechanism during adjustment. Because the drive block moves, it is difficult to install a conventional drive system to the recliner mechanism. This is a particularly significant problem when a power drive system is desired. While it is typically possible to interconnect the moving drive block with a stationary drive motor using a flexible drive cable, the cable will move linearly with the drive block and therefore will require special packaging and design of other seat components. For example, other seat components cannot be located in the space through which the cable will travel during operation of the adjustment mechanism. Further, in some seat assemblies, the rail mechanism and/or other seat components must be slotted to accommodate the moving cable. This weakens the rail mechanism and increases the cost of manufacture of the seat assembly.